Aussie,

Are you supplementing with calcium/magnesium complex? Muscles require sufficient magnesium to relax, and nerves require magnesium to stop firing when appropriate. If you take antacids or acid blockers, you are probably not absorbing enough magnesium for your body's needs. Magnesium deficiency can cause a tendency to twitch, cramps, or tremors.

A good calcium/magnesium supplement has approximately two calcium atoms for one of magnesium. Both would be in highly absorbable form: acid salts, chelated with amino acids, or to a lesser degree oxides. Basic salts such as carbonates or hydroxides are even less absorbable. Magnesium hydroxide is milk of magnesia, a potent laxative. From the Wikapedia article, "only a small amount of the magnesium from milk of magnesia is usually absorbed from a person's intestine". If you supplement with calcium/magnesium (you should take both if you take either), you also need about 400 i.u. of vitamin D to enable the body to utilize the calcium.

Don't overdo the amounts. Too much calcium/magnesium stresses the kidneys and can lead to painful kidney stones.

The following links are examples of pretty good supplemental calcium/magnesium:

http://www.iherb.com/store/ProductDe...&pid=CLF-02481

http://www.iherb.com/store/ProductDe...&pid=CLF-02522

http://www.iherb.com/store/ProductDe...&pid=NWY-41311

http://www.iherb.com/store/ProductDe...&pid=JRW-13012 (caution: too much magnesium citrate is highly laxative)

http://www.puritan.com/pages/file.as...CID=1&CPID=696 (calcium carbonate is cheap and not absorbed well)

http://www.puritan.com/pages/file.as...CID=1&CPID=740

I can recommend both vendors, but there are plenty of great vendors out there. Mainly, these are the kinds of ingredients you should look for, in these proportions.